Even for the politics that "got us the 40 hour work week and the weekend", I think the integration is problematic. Essentially Facebook has traditionally been a social network first, and many people's Facebook activity feed reflect more what they do "off hours" and are more conversational in nature. It is relatively easy to skim profile feeds (entire histories of data), and it just seems like it isn't a big step to imagine nefarious employers running sentiment analysis on Facebook timelines just to eliminate characteristics they don't like... including characteristics it is illegal to discriminate against now.

For instance, in the politics that "got us the 40 hour work week and the weekend" it is illegal to overtly not hire someone just because they expressed sympathetic pro-union views (https://www.nlrb.gov/rights-we-protect/whats-law/employers/d...). But what stops an employer with direct links to a profile from running analysis on posts exactly for that? Such a thing it seems would be hard to detect.